This invention relates to a control strategy of variable geometry intake manifolds for engines and charge motion control valves.
Variable geometry intake manifolds for engines are known. In an intake manifold with variable geometry, the intake air is controlled to different runners to provide varying conditions at the intake port of the cylinder. In operation, air may be directed through a low-speed runner which may comprise a longer path for the intake air and a high-speed runner which may be a more direct path to the intake port. In order to control the intake air, valves at the start of the high-speed runner may be provided. These valves, when closed, direct the intake air down the low-speed runner. When open, these valves allow a more direct route to the intake port down the high-speed runner. The high speed runner is usually closed off during low-speed and low-power requirement conditions. During high-speed or high-power conditions, the high-speed runner is usually open.
A charge motion control system is known incorporating charge motion control valves near the intake port. The charge motion control valves provide a tumble to the incoming intake air at or near the intake port of the cylinder. The tumble motion is usually imparted on the intake air by the charge motion control valve restricting or closing most of the cross-section of the intake port manifold. This allows the incoming intake air to be diverted through a smaller cross-sectional area and thereby produce a downstream tumble which, then, proceeds into the intake port and cylinder to provide a mixing motion.
An aspect of the invention is to integrate the control system for the variable geometry manifold and the charge motion control device for internal combustion engines. By integrating these controls, the overall control strategy is simplified.
This aspect may be achieved by a tuning valve for an internal combustion engine with a barrel valve arranged adjacent to an intake port of a cylinder and operable in a first position to close a high-speed runner of the variable geometry manifold. The barrel valve, in a second position, operatively closes the high-speed runner and provides charge motion control to intake air and a low-speed runner. This reduces the complexity of the inlet manifolds with inlet port charge motion control devices and with variable configuration air paths by way of movable valves by performing both functions with the same device. Thus, two independent devices for manifold geometry configuration, namely, variable geometry manifolds for the use of manifold tuning valves and charge motion control valves for in-cylinder burn rate improvement, are not required in that one valve operatively controls both the charge motion control and the variable geometry manifold.
The barrel valve can be a segment of between 45xc2x0 and 180xc2x0. Preferably, the barrel valve is approximately a quarter-barrel. The barrel valve is rotatable from a first position which provides no reduction in intake port cross-section where the barrel valve is rotated flush with the intake port side. In a second position, the barrel valve rotates to close the high-speed runner but does not reduce the cross-section of the low-speed runner. In the second position, a radius of the barrel valve connects a side of the low-speed runner to the intake port side. In a third position, the barrel valve rotates fully closed to restrict the low-speed runner cross-section. In this position, a small distance is located between the low-speed runner and the barrel valve circumference. This distance or space provides a point of maximum velocity which induces mixture motion or tumble to the incoming intake air in the intake port. The circumference of the barrel valve is located upstream in this position, and the radius is located downstream providing a reduced cross-section to the intake port.
In certain preferred embodiments, a tuning valve is arranged in an internal combustion engine. The internal combustion engine has a variable configuration air intake manifold with a low-speed runner and a high-speed runner. The engine includes a cylinder head for a combustion cylinder, the cylinder head having an intake port for intake air for the cylinder. The tuning valve is arranged between the runners and the intake port and operably closes the high-speed runner to vary the configuration of the intake manifold. The tuning valve also operates to impart a charge motion control to the intake air via the low-speed runner. The tuning valve may be a blade-type valve.
In a preferred embodiment, a tuning valve is a barrel valve, of a 45xc2x0 to 180xc2x0 segment. Preferably, the tuning valve is a barrel-valve of approximately a 90xc2x0 segment. The tuning valve may operate to throttle the engine.
Preferably, the tuning valve rotates to supply a full range of flow restrictions from part-load to fully closed.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.